2-aminoethyl Methacrylate Hydrochloride Research Articles

Synthesis of latex particles with surface amino groups

Monodisperse latex particles with surface amino groups were prepared by a two-step emulsion polymerization. In the first step, the seeds were synthesized by batch emulsion polymerization of styrene; and in the second step, two different amino-functionalized monomers [aminoethylmethacrylate hydrochloride (AEMH) and vinylbenzylamine hydrochloride (VBAH)], two different initiator systems (K2S2O8 and K2S2O8/Na2S2O5) and mixtures of emulsifiers sodium dodecylsulfate (SDS) and Tween 21 were used to synthesize the final latexes. To characterize the final latexes, conversions were obtained gravimetrically and particle size distributions and average particle diameters were determined by transmission electron microscopy (TEM) and photon correlation spectroscopy (PCS). The amount of amino groups was determined by the SPDP (N-succinimidyl 3-(2-pyridyldithio)propionate) method. The influence of the different conditions used to synthesize the latexes on the colloidal stability of the particles was evaluated by measuring the diameters of the final latexes dispersed in solutions at different pHs and ionic strengths. The most stable latexes were obtained using the smallest seed, VBAH monomer, and the K2S2O8/Na2S2O5 initiator system. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4230–4237, 2000

Cationic amino-containing N -isopropyl- acrylamide-styrene copolymer latex particles: 1-Particle size and morphology vs. polymerization process

Cationic hydrophilic copolymer latexes were synthesized at 70 °C either by batch or two-step emulsifier-free emulsion poly-merization of styrene (St), N-iso-propylacrylamide (NIPAM), and aminoethylmethacrylate hydro-chloride (AEM) using 2,2′-azobis (2-amidinopropane) dihydrochloride as initiator. At first, batch polymerization kinetics were followed by gas chromatography (GC), revealing that NIPAM rapidly homopolymerized, before the polymerization of styrene had started. Particle size analysis by quasi-elastic light scattering (QELS) and transmission electron microscopy (TEM) showed that monodispersed particles were obtained with the formation of a poly[NIPAM] rich shell. Adding a small amount of the cationic monomer caused a strong decrease of the particle size without affecting the size monodispersity. When a shot process was used, a narrow particle size distribution was maintained, provided that the monomer addition was performed at a relatively high conversion of the first batch step. The poly[NIPAM] rich shell layer was larger with the shot process, but increasing the amino-containing monomer in the recipe resulted in a dramatic decrease of the thickness. Combination of transmission, scanning and atomic force microscopy techniques showed that these hydrophilic particles exhibited odd-shaped structures, the unevenness being dependent upon the performed process. Kinetic data and particle morphology information were inferred for discussion of the polymerization mechanism of this system.

Emulsifier‐free emulsion copolymerization of styrene with two different amino‐containing cationic monomers. I. Kinetic studies

The kinetics of emulsifier-free emulsion copolymerization of styrene were investigated in the presence of two amino-containing monomers, aminoethyl methacrylate hydrochloride (AEMH) and vinyl benzyl amine hydrochloride (VBAH), using 2,2′-azobis(2-amidinopropane) dihydrochloride (V50) as a cationic initiator. At first the partition coefficient of AEMH and VBAH in a water-styrene mixture were measured, indicating a strong hydrophilicity for both monomers; kinetics of solution homopolymerization, as followed by 1H-NMR, in water provided high values at 4.0 and 1.75 (L mol−1 s−1)1/2 for AEMH and VBAH, respectively. The two monomers were found to similarly affect the kinetics of emulsion copolymerization of styrene: the overall polymerization rate and particle number increased dramatically upon increasing the functional monomer concentration; the average number of radicals per particle (n) was dependent upon the particle size, reaching a 0.5 value for particle size below 100 nm; and the molecular weight of polymer samples decreased with the functional monomer concentration, revealing the strong activity of VBAH and AEMH in the chain transfer. The polymerization mechanism in the presence of VBAH and AEMH was discussed, referring to the coagulation nucleation mechanism to explain the formation of a large particle number. Using the method proposed by Gilbert et al., transfer rate constants were determined for each monomer (around 10 L mol−1 s−1) and styrene (4.5 10−2 L mol−1 s−1). © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2315–2330, 1997

Emulsifier-free emulsion copolymerization of styrene with two different amino-containing cationic monomers. I. Kinetic studies

The kinetics of emulsifier-free emulsion copolymerization of styrene were investigated in the presence of two amino-containing monomers, aminoethyl methacrylate hydrochloride (AEMH) and vinyl benzyl amine hydrochloride (VBAH), using 2,2′-azobis(2-amidinopropane) dihydrochloride (V50) as a cationic initiator. At first the partition coefficient of AEMH and VBAH in a water-styrene mixture were measured, indicating a strong hydrophilicity for both monomers; kinetics of solution homopolymerization, as followed by 1H-NMR, in water provided high values at 4.0 and 1.75 (L mol−1 s−1)1/2 for AEMH and VBAH, respectively. The two monomers were found to similarly affect the kinetics of emulsion copolymerization of styrene: the overall polymerization rate and particle number increased dramatically upon increasing the functional monomer concentration; the average number of radicals per particle (n) was dependent upon the particle size, reaching a 0.5 value for particle size below 100 nm; and the molecular weight of polymer samples decreased with the functional monomer concentration, revealing the strong activity of VBAH and AEMH in the chain transfer. The polymerization mechanism in the presence of VBAH and AEMH was discussed, referring to the coagulation nucleation mechanism to explain the formation of a large particle number. Using the method proposed by Gilbert et al., transfer rate constants were determined for each monomer (around 10 L mol−1 s−1) and styrene (4.5 10−2 L mol−1 s−1). © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2315–2330, 1997

Emulsifier-free emulsion copolymerization of styrene with two different amino-containing monomers: II. Surface and colloidal characterization

The colloidal and surface properties of copolymer latex particles prepared by batch emulsifier-free emulsion polymerization of styrene with two different amino-containing monomers (Amino Ethyl Methacrylate Hydrochloride (AEMH) and Vinyl Benzyl Amine Hydrochloride (VBAH)), and 2,2′-azobis(2-amidinopropane) dihydrochloride (V50) as initiator were investigated. The final particle size was found to decrease with increasing the functional monomer concentration. Different titration methods were used to quantify the surface amino (brought by the monomer) and amidino groups (originated from the initiator) on the latex particles. The same behavior was observed on both type of latexes: increasing the functional monomer concentration caused the surface amino groups density to increase from 0 to a plateau value at 8.2 μC/cm2, whereas the surface amidino groups density decreased from 18.5 to 2 μC/cm2. These results were confirmed by electrophoretic measurements and they corroborated those obtained in a previous kinetic study (Part 1) concerning the role of functional monomers as transfer agents. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2331–2342, 1997

Emulsifier‐free emulsion copolymerization of styrene with two different amino‐containing monomers: II. Surface and colloidal characterization

The colloidal and surface properties of copolymer latex particles prepared by batch emulsifier-free emulsion polymerization of styrene with two different amino-containing monomers (Amino Ethyl Methacrylate Hydrochloride (AEMH) and Vinyl Benzyl Amine Hydrochloride (VBAH)), and 2,2′-azobis(2-amidinopropane) dihydrochloride (V50) as initiator were investigated. The final particle size was found to decrease with increasing the functional monomer concentration. Different titration methods were used to quantify the surface amino (brought by the monomer) and amidino groups (originated from the initiator) on the latex particles. The same behavior was observed on both type of latexes: increasing the functional monomer concentration caused the surface amino groups density to increase from 0 to a plateau value at 8.2 μC/cm2, whereas the surface amidino groups density decreased from 18.5 to 2 μC/cm2. These results were confirmed by electrophoretic measurements and they corroborated those obtained in a previous kinetic study (Part 1) concerning the role of functional monomers as transfer agents. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2331–2342, 1997

Free Solution Capillary Electrophoretic Separation of Basic Proteins and Drugs Using Cationic Polymer Coated Capillaries

A simple capillary coating which exhibits reversed (anodic) electroosmotic flow (EOF) has been developed for the separation of cationic compounds by free solution capillary electrophoresis. Poly(2-aminoethyl methacrylate hydrochloride) (PAEM) was chemically bound onto the fused-silica capillary inner wall. Capillaries modified by this method exhibit an essentially pH-independent EOF in the pH range from 3 to 5.5, and have been applied to the improved separation of basic proteins and drugs (e.g., beta-adrenergic blocking drugs). High efficiency and precise migration (relative standard deviation was less than 1%) were observed.